防溶解抗烧结单原子层结构有序Pt基合金催化剂的构筑与性能调控

发展低成本、高性能的氧还原催化剂是实现燃料电池商业化的关键。针对现有碳载Pt基催化剂存在的Pt原子利用率低、活性和稳定性差等问题。本申请提出“防溶解抗烧结单原子层结构有序Pt基合金催化剂的构筑与性能调控”方案，利用原子级分散过渡金属与杂原子共掺杂碳基底材料对Pt盐前驱体的锚定作用，控制Pt仅沿载体表面进行二维生长，制备单原子层Pt负载催化剂，使全部Pt原子暴露在催化剂表面；然后利用高温下Pt与过渡金属原子重排行为与二氧化硅的空间限域作用，直接将单原子层Pt转化为单原子层结构有序Pt基合金，利用单原子层Pt基合金与载体间的强相互作用，抑制单原子层Pt基合金催化剂在载体表面的迁移、团聚长大及助催化组分溶解失活，实现催化剂活性和稳定性全面提升。

Developing catalysts with low cost and high performance for oxygen reduction reaction (ORR) has been one of the major challenges for large-scale application of fuel cells. At present, Pt and its alloy nanoparticles (NPs) adsorbed on carbon support are the most available electrocatalysts for ORR, but their practical use in PEMFCs was impeded by relatively low Pt utilization, activity and stability. .To enhance and optimize catalyst performance and durability for the ORR in fuel cell applications, we look beyond conventional Pt-based NPs and describe a new class of structurally ordered single-atomic-layer Pt-based alloy nanocatalyst, where all Pt atoms are located at the surface and can be utlized by ORR. The synthesis of single-atomic-layer Pt is achieved by utilizing the strong anchoring effect of atomically dispersed transition metal (M) and heteroatom co-doped carbon (M-H-C) support on Pt precursor, which enables Pt atoms to grow and spread only in two-dimensional directions with one atom or few atoms in height. The catalytic performance of single-atomic-layer Pt can further been improved by alloying Pt with a second non-noble metals through a thermally driven interfacial diffusion route. The strongly metal-support interaction between structurally ordered single-atomic-layer PtM alloy and M-H-C can effectively prevent single-atomic-layer PtM alloy from detachment, migration and aggregation during PEMFCs working conditions. Moreover, the leaching of non-noble metals can be significantly alleviated due to the definite composition and structure of structurally ordered single-atomic-layer PtM alloy.